Cost & material estimator
Pergola Cost & Material Estimator
Pergola results are product pages and price ranges. This gives you the lumber list: posts, beam size for your actual span, rafter count, board feet, footings and concrete.
- Post count and length, and how attaching it halves them
- Beam size selected from your post spacing
- Rafter and purlin counts at your spacing
- Board feet, footing depth and concrete bags
- Build vs kit vs installed, side by side
- Permit and span warnings before you order
Pergola Cost & Material Estimator — interactive tool
Dimensions
Western red cedar — 20–30 years. Naturally rot-resistant, stable, and considerably better-looking. The usual choice where the pergola is a feature rather than a utility.
Spacing, frost depth and prices
Closer spacing gives more shade and costs more. 24 in is standard.
Footings must go below it. 0 in mild climates; 36–48 in across the northern US.
12 × 12 ft · freestanding · Western red cedar
Your pergola take-off
in materials — a kit runs $4,896–$8,352, installed $9,544–$15,376
- Posts
- 4 × 6x6
- Beams
- 2x12 (doubled)
- Rafters
- 7 × 2x8
- Board feet
- 528.7
- Footings
- 32 in
- Concrete
- 28 bags
Western red cedar — 20–30 years. Naturally rot-resistant, stable, and considerably better-looking. The usual choice where the pergola is a feature rather than a utility.
Home & Garden Living · homeandgarden.living/tools/pergola-cost-calculator
Check permits and setbacks before ordering anything
A 144 sq ft freestanding pergola will very likely need a permit. Thresholds vary by municipality and are commonly around 100–200 sq ft for freestanding structures, with anything attached to the house treated more strictly. Setback rules govern how close to the boundary you can build, and HOAs impose separate limits.
These spans are planning rules of thumb, not an engineered table
Real span capacity depends on species, grade, and local snow and wind loading. The figures here are deliberately conservative for planning purposes. If you're in a heavy snow region, adding a solid or louvred roof, or spanning beyond about 12 ft, have the structure sized properly.
Standoff post bases, not posts in concrete
Setting a timber post directly into concrete traps water at the base and the post rots from the bottom. Use standoff post bases that hold the post an inch above the footing. It's a small hardware cost and it roughly doubles the life of the structure.
Call 811 before digging footings
4 footings at 32 in deep is more than deep enough to reach buried services.
| Item | Quantity | Cost |
|---|---|---|
| 6x6 posts (10 ft, ground-contact rated)Both sides on posts | 4 | $1,058 |
| 2x12 (doubled) beamsSized for a 12 ft post spacing (rule-of-thumb limit 12 ft) | 51 linear ft | $1,799 |
| 2x8 rafters at 24 in on centreSpanning the 12 ft projection | 7 at 13.5 ft | $1,114 |
| 2x4 purlinsAcross the rafters — this is the layer that actually produces the shade pattern | 9 at 13 ft | $691 |
| Post bases, brackets and structural fastenersStandoff post bases keep the post end out of standing water — this is what decides whether the post rots | 4 sets | $312 |
| Concrete for footings32 in deep footings | 28 × 60 lb bags | $190 |
| Stain or sealerSeal all faces including end grain before assembly | 3 gal | $138 |
| Materials total (DIY) | $5,302 | |
Build, kit, or hire
Build from lumber
$5,302
About 32.8 hours. Full control over dimensions and detailing.
Kit
$4,896–$8,352
Bolt-together and dimensionally exact. The only realistic route to motorised louvres.
Installed
$9,544–$15,376
Worth it for an attached pergola if you're unsure about the ledger connection.
- Area
- 144 sq ft
- Post spacing limit
- 12 ft
- Purlins
- 9
- Build time
- ~32.8 hr
Your shopping list
$5,302Structure
Hardware
Finish
Take these numbers further
What this estimate assumes
- · Beam and rafter sizing uses conservative planning rules of thumb for pergola loads, not an engineered span table. Species, grade and local snow load all matter.
- · An attached pergola carries one side on a ledger and therefore needs half the posts of a freestanding one of the same size.
- · Footings are the deepest of: 30 in, one third of post height, or your frost depth. Attached pergolas use 24 in as the floor.
- · Board feet are calculated from nominal cross-sections; material price scales from your board-foot price by the material factor.
- · Kit and installed ranges are 2026 US per-square-foot figures, higher for louvred systems.
- · If you're in a heavy snow region, adding a solid or louvred roof, or spanning beyond about 12 ft, have the structure sized properly rather than estimated.
Spans here are conservative planning rules of thumb. For heavy snow, a solid roof, or long spans, have the structure sized properly.
Search for pergola costs and you get two things: retailer pages for kits, and articles quoting a range so wide it tells you nothing. Neither answers the question a person planning one actually has, which is what it takes to build the thing at the size they want.
So this produces a take-off. How many posts for a 16-foot span, what beam size that spacing needs, how many rafters at 24 inches on centre, the board feet, the footing depth for your frost line, and the concrete. Then it prices the same structure three ways — built from lumber, bought as a kit, and installed by someone else — because those three routes differ by a factor of three and most people have never seen them compared.
Two honest limits, stated up front rather than buried. The span figures here are conservative planning rules of thumb, not an engineered span table: real capacity depends on species, grade and local snow load. And an attached pergola hangs off the house structure, which makes the ledger connection the critical detail and a good reason to involve a carpenter if you're not certain what's behind the cladding.
The span rules this estimator uses
Beam size follows from post spacing, and post spacing follows from how wide the pergola is. These are the conservative end of common practice for pergola loading — deliberately, because the failure mode of an oversized beam is spending an extra $80, and the failure mode of an undersized one is a structure that sags and eventually fails.
If your post spacing works out beyond about 12 feet, or you're in a heavy snow region, or you're adding a solid or louvred roof, these rules of thumb stop being adequate. That's the point to have the structure sized by someone qualified rather than estimated by a web page.
| Member | Size | Max span | Notes |
|---|---|---|---|
| Beam | 2×8 doubled | 8 ft | Typical for a small pergola with posts at each corner |
| Beam | 2×10 doubled | 10 ft | The usual size for a 10–12 ft structure |
| Beam | 2×12 doubled | 12 ft | Beyond this, add a post or get it engineered |
| Rafter | 2×6 | 10 ft | At 24 in on centre |
| Rafter | 2×8 | 13 ft | At 24 in on centre |
| Rafter | 2×10 | 16 ft | At 24 in on centre |
Conservative maximum spans for pergola loading. Planning rules of thumb, not an engineered span table.
Attached or freestanding
An attached pergola carries one long side on a ledger fixed to the house, which halves the post count and generally reduces the cost. It also introduces the single most consequential detail in the whole project.
The ledger must fasten into the house framing — not into sheathing, not into siding — with structural fasteners, and it needs flashing above it. Get the fastening wrong and it's a structural failure waiting to happen. Get the flashing wrong and you've created a permanent route for water into the wall, which does its damage silently for years.
It also makes a permit considerably more likely: attaching a structure to the house is treated more strictly than a freestanding one almost everywhere. If you're not confident about identifying framing behind the cladding, this is the point to bring in a carpenter for a day. The rest of the build is straightforward.
Open, canopy, or louvres
An open-rafter pergola gives dappled shade, sheds wind, and carries almost no snow. It's the cheapest option and it's what most people picture — but it's worth being clear that at midday in summer it provides considerably less shade than the photographs suggest, and against low afternoon sun it does very little.
A retractable canopy adds real shade and modest cost. An adjustable louvre roof is the best-performing option by a distance — full shade to full sun on demand, and rain cover with the louvres closed — and it's where most of the money goes on a high-end pergola.
The important structural point: adding any roof changes what the structure is. An open pergola lets wind through and snow fall through. A covered one collects snow load and catches far more wind, which means the whole structure needs sizing for it. It also makes a permit near-certain.
- Purlins across the rafters are what actually produce the shade pattern on an open pergola — closer spacing, more shade.
- Orient rafters to run the direction that blocks your worst sun hour, not simply the shortest span.
- Standoff post bases, never posts set directly into concrete.
- Seal every face including the end grain before assembly. It roughly doubles the structure's life.
Build, kit, or hire
Building from lumber gives full control over dimensions and detailing, and it's the cheapest route by a comfortable margin. It's genuinely achievable for anyone who's built a deck, and it's a lot of drilling and lifting.
A kit is bolt-together, dimensionally exact, and arrives with the engineering done. Aluminium kits are the only realistic route to motorised louvres. You're paying for the engineering and the certainty rather than the material.
Installed pricing is roughly two to three times the material cost. It's most worth it for an attached pergola where the ledger connection matters, on a site where the footings need real thought, or where a permit and inspection are involved and you'd rather someone else owned that.
What this tool assumes
Every number this tool produces rests on these. Change your inputs and they change with you.
- Beam and rafter sizing uses the conservative planning rules of thumb published above, not an engineered span table.
- An attached pergola carries one side on a ledger and needs half the posts of a freestanding one of the same size.
- Footings are the deepest of 30 in, one third of post height, or your local frost depth. Attached pergolas use 24 in as the floor.
- Board feet are calculated from nominal cross-sections; material price scales from your board-foot price by the material factor.
- Kit and installed ranges are 2026 US per-square-foot figures, higher for louvred systems.
- Costs are estimates, not quotes.
Mistakes that cause rework
Each of these costs money or a whole weekend to undo.
Setting posts directly in concrete
It traps water at the base of the post and it rots from the bottom, invisibly. Standoff post bases hold the post an inch clear and roughly double the structure's life for a small hardware cost.
Undersizing the beam for the span
Post spacing drives beam size. A doubled 2×8 is fine at 8 ft and inadequate at 12. Sagging beams can't be fixed without dismantling the roof.
Attaching a ledger to sheathing or siding
The ledger has to fasten into framing with structural fasteners, and it needs flashing above it. This is the connection that fails, and when it fails it takes the pergola down.
Adding a roof to a structure sized for open rafters
A canopy or louvres turns a wind-permeable frame into a roof that collects snow and catches wind. The structure has to be sized for that from the start.
Not sealing the end grain
Cut ends absorb many times more water than faces, and once assembled you can't reach them. Seal everything before it goes together.
Building before checking setbacks
Permit thresholds are commonly around 100–200 sq ft for freestanding structures, lower for attached. Setbacks govern how close to the boundary you can build. Find out before the lumber is delivered.
Safety & honest limits
- Roofed and attached structures generally need a permit above a modest footprint, and setback rules vary by municipality. Check before ordering materials.
- An attached pergola's ledger connection is structural. It must fasten into house framing with structural fasteners and be properly flashed. If you're unsure, involve a carpenter.
- Span figures here are conservative planning rules of thumb. For heavy snow regions, covered roofs, or spans beyond about 12 ft, have the structure sized by a qualified designer.
- Call 811 before digging footings.
- Use ground-contact rated lumber for anything below grade, and standoff post bases rather than setting posts in concrete.
- Cutting treated lumber produces dust that shouldn't be inhaled. Cut outdoors with a mask and eye protection, and never burn treated offcuts.
- Costs are estimates, not quotes.
Frequently asked questions
How much does a pergola cost?
Built from lumber, roughly $1,500–4,000 in materials for a 12×12 ft cedar pergola. A kit for the same size runs $4,000–8,000, and installed pricing is typically $5,000–12,000. Louvred roof systems sit well above all three ranges.
What size beam do I need for a pergola?
It depends on the post spacing. As conservative planning rules of thumb: a doubled 2×8 spans about 8 ft, a doubled 2×10 about 10 ft, and a doubled 2×12 about 12 ft. Beyond that, add a post or have it engineered — species, grade and snow load all matter.
Is an attached or freestanding pergola better?
Attached uses half the posts and costs less, but the ledger connection into the house framing is the critical detail and a permit is more likely. Freestanding is structurally simpler and can go anywhere in the yard. If you're not confident identifying framing behind the cladding, freestanding is the safer DIY project.
Do pergolas need footings?
Yes. Post footings go the deepest of about 30 inches, one third of the post height, or below your local frost line. Use standoff post bases rather than setting posts directly into concrete — a post in concrete rots from the base.
Do I need a permit for a pergola?
Usually above a certain footprint — often around 100–200 sq ft for a freestanding structure, and lower or automatic for anything attached to the house or with a solid roof. Setback rules also govern how close to the boundary you can build. Ask your building department before ordering.
How much shade does a pergola give?
An open-rafter pergola gives dappled shade — less at midday than photographs suggest, and very little against low afternoon sun. Closer purlin spacing helps. For real shade you need a canopy or adjustable louvres, which changes the structural requirements.
What is the best wood for a pergola?
Cedar for most people: naturally rot-resistant, stable, and considerably better-looking than treated pine at about twice the price. Pressure-treated pine is entirely serviceable and needs sealing every two to three years. Select the boards yourself either way — twisted stock is common.
Last reviewed July 25, 2026 · Home & Garden Living
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